Magnesium-alloy-block edge-active driving belt



Aug. 4, 1953 P. B. REEVES 2,547,410

MAGNES IUM-ALLOY-BLOCK EDGE-ACTIVE DRIVING BELT I Filed July 3, 1950 E:-E Q} I 135 5-:

IN V EN TOR.

- Array ray Patented Aug. 4, 1953 FI fiTUNITED' STATE-S PATENT OFFICEPaul B. Reeves, Columbus, Ind., assignor to Reeves Pulley Company,Columbus, Ind., a corporation of Indiana Application July 3, 1950,Serial No. 171,783 3 Claims. (01. 74-236) The present invention relatesto power transmission belts, andmore particularly to the type ofbeltsintended to cooperate with coned sheaves, andv comprising a band or webof material ofhigh tensile strength but readily flexible bothlongitudinally and laterally, carrying a longitudinally spaced series oftransversely extending stiffener blockunits. The invention isparticularly directed to such stiffener blocks; and the primary objectof the invention is to provide an improved form of stiffener block foruse in such an environmentl .Belts'of the character here underconsideration find'their primary utility in speed varying transmissionunits of the character widely known as the .---R.eeves type. Such atransmission comprises a pair of parallel shafts on each of which ismounted a sheave made up of mating coned disc's, the discs of eachsheave being axially relatively adjustable, and the two sheaves beingdrivingly' connected through the medium of an edgeactive belt. Thelateral edges of such a belt must frictionally engage the facing conedsurfaces of the discs of the respective pulleys in order to provide adriving connection therebetween; but the belt edges must be movable,radially of the discs, during adjustment of the discs. The belt bodymust, of course, flex readily about transverse axes at it turns aroundthe sheaves; but it must be rigid, withrespect tolongitudinally-extending axes,.in order that it may sustain the pressuretransverse- 1y exerted against the belt by the mating discs. Thattransverse rigidity is provided by the stillener blocks-jto which thisdisclosure, is primarily directed.

Since the original invention of this type of transmission, and untilvery recent years, it has been the universal practice to use woodenstillener blocks nailed to the flexible belt band, and provided, attheir laterally opposite ends, with tips of suitable friction materialnailed to the blocks. Wood has been used, in preference to othermaterials, because the ratio of its weight to its compression strengthis more advantageous than that of other materials heretofore availablefor such use. Excessive weight, obviously, is undesirable, since thebelts m-ove at relatively high speed so that centrifugal forces, as theblocks turn about the pulleys, can become highly detrimental to theoperation of the transmission. Such forces tend to increase the tensilestresses applied to the belt band, and also tend to move the beltradially outwardly with respect to the cone faces, thus tending to relaxthe frictional engagement between the cone faces and the block tips.

Some experimental Work with metal belt blocks has been done within thepast several years; but, prior to my invention, the art has not beenable to develop any metal belt block possessing a satisfactory ratio ofweight to compressive strength. Thishas been due, in part, to thefailure of the art to evolve a block design which, while utilizing aminimum mass of material, will provide a satisfactory strength.

It is an ancillary object of the present invention to provide a specificshape of stiffener block which, when embodied in a magnesium-alumi-,numalloy, will meet the requirements of a metal stiffener block to beused in a belt of the character here under consideration.

' ings, attention being called to the. fact, however,

that the drawings are illustrative only, and that change may be made inthe specific construction illustrated and described, so long as thescope of the appended claims is not violated.

Fig. lis a plan view of a fragment of a belt of the character here underconsideration, constructed inaccordance with the present invention;

Fig. 2 is a bottom plan view of a block constructed in accordance withthe present invention;

Fig. 3 is a transverse section through the belt of Fig. 1 showing oneblock in elevation;

Fig. l is a central section through such a block;

Fig. 5 is an end elevation of such a block, taken upon aenlarged scale;and

. Fig. 6 .is alongitudinal section, taken substantially on the line 6, 6of Fig. 3, and drawn to the scale of Fig. 5.

' -Referringmore particularly to the drawings,

it will be seen that I have illustrated a fragment of a belt band II!which may be of conventional character, a longitudinally spaced seriesof transversely-extending stiffener blocks, indicated generally by thereference numeral I I, being secured thereto in accordance withconventional practice as described above.

Each block I l comprises a transversely-extending beam I2 and a clampingplate l3, together with means, such as the screws M, for clamping thebeam and the plate to the belt band I0 in a manner which will bedescribed in further detail hereinafter.

At it opposite ends, the beam I 2 integrally carries wing members l6 andI1. Said members t6 and I! are formed to provide laterally outwardlypresented faces [8 and 19 which are allochirally inclined to the planeindicated by the section line 6, 6. Each such face inclines outwardlyand upwardly from its inner or lower end 22 to its :outer .or upper end4 23. .A pad 28 ref friction .material iis :aiihesively secured ":to theface I 8 and a similar pad 2| is similarly secured to the face IS.

The beam 12 is formed to provide an upwardlyfacing plane surface 24whose transverswextent is substantially equal to the transversedimension of the band [0, and which ,is engaged with the inner surfaceof the band. .Each wing member l and I7 comprises a portion 25projecting upwardly beyond the beam I2 and a portion 26 projectingdownwardly beyond the 'beam l2; and each such portion tapers inthickness, in ithe .direction of length of the beam l2, as it retreatsfrom said beam.

Thelower nrfinner surface of the beam 12 is provided with a median,longitudinally-extending, re'inforcing rib28 .of substantial depth; andwith two further reinforcing ribs 29 and '30 located at its oppositeedges. I'have found, by experimentation, that the three ribs thusprovided, and extending continuously between the roots of the wingmembers 16 and 11, provide the strength necessary for sustainingth'ec'ompressive stresses which "are applied (to these blocksin use.

The lower surface of the beam 12 is further provided with two laterally"spaced bosse 331, 3! which are ceritra'llypenetrated by tapped bores orsockets 32, '32 for the'reception of the clamping screws .M. Theseperforations are desirably located within the rib 28, "as shown.

In use, thebelt band .IOis supported upon the surface "24 of the --beamI2. -iuplate i3 is then located on the outer surface of the band ill, inregistry :with the beam 12, and screws M are passed through the plateand the band I9 and are entered in the bores 32 and turned down untilthe screw "heads clamp *the "band between the'p'la'te 3 "and'the surface24 of the beam l2.

It is desirable "that the belt band'shall =be' located substantially inthe plane :bisecting the lengths 'ofthe faces IBan'd H) *of the wingmembers i6 and H. To this end, the surface it is preferably located in aplane depressed below said bisecting plane by'anamcun't not exceedingone-half the thickness of the band I I].

I have found that an optimum shape for the surfaces -'i'8 and I'll, andfor the pads and =2! carried thereby, is that illustrated in Fig. 5, inwhich said surfaces flare uniformly from their inner ends to their"outer ends, as shown.

I presently believe the details ofsconstruction of'the block, as herein'disclosed and claimeid, to be optimum, 'and that any substantialdeparture from the structure defined in the appended claims will have adeleterious -efie'ct up0n the 'belt as a whole, when used in anenvironment of the character above described. The specific structureshown, when embodied in a magnesiumaluminum alloy, provides a ratio ofweight to compressive strength at least as satisfactory as thatpossessedbythe wood blocks used effectively foriso manygyeargprior 5120the invention. Manufacturing expense, on the other hand, issubstantially reduced by the use of blocks constructed in accordancewith the present invention.

1 claim :as any invention:

I. "A belt comprising a body strand of mate- ,rialiof high .tensilestrength but readily flexible depth c-longitudinally and laterally, anda plurality of longitudinally-spaced, transverselyrigid stifiener blocksecured to said body, each (if said "blocks comprising a transverse beamintegrally carrying members at its opposite ends formed to provideoppositely-facing surfaces allochirallyiangularly related to a planeperpendicular Jto said beam, one surface of said beam engaging .theinner surface of said body, .the "opposite surface of ,said beam beingprovided with a pentral rib .and .two flanking ribs extending from one.to the other-of saidmembers, a clampingplate engaging'the outer surfaceof "said "body in registry with said beam, 'and'means penetrat ing saidbody and "engagingsaid beam ,and "said plate to secure saidbeaman'd'p'lateto saidbo'dy.

2. A transverse 'stifi'ener block for belts "comprising a "transversebeam integrally carrying members at its oppositeends formed .to presentoppositely-facing surfaces allochirally "angularly related ,to a planeperpendicular "to .said beam, said faces projecting abcveandbelowthemedian plane of said beam, said "beam being formed with 'an upwardly-presented 'sur'fa'ce 'extending continuously between said menibera-theopposite surface of said "beam being formed to provide "ameclian,longitudinallyextending, reinforc'ingrr'ib and twolongitudinallyextending, "reinforcingr'ibsat its oppositeedgesya clampplate for coop'eration'with'said beam surface-to clamp therebetween aportion-of a belt 'b'and, andmeans cooperating "with 'said ,beam 'andsaid plate to urge said plate toward said beam surface.

3."The block of claim "2 in which said lastnamed means comprises aplurality of "screws penetrating said'plate'andthreadedly engaged insockets *formedin said'beam and locatetlin said median rib.

PAUL-B.

-Re'ferences Uite'd in the file OT this patent UNITED STATES PATENTSNumber :Name Date 1 3546304 Barker July :21, 1 925 2522 466 .Perry-5June2'2, 1-943 ;2;406,253 Reeves .Aug. 320, 21 9416

